Fire-alarm signal-box



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' G. M. STEVENS.

FIRE ALARM SIGNAL BOX. 4

No. 379,339. PatentedMar. 13, 1888.

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G. M. STEVENS.

FIRE ALARM SIGNAL BOX.

Patent-ed Mar. 13, 1888.

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UNTTED STATES PATENT OFFICE.

GEORGE M. STEVENS, OF CAMBRIDGE, MASSACHUSETTS.

FIRE-ALARM SlGNAL-BOX.

SPECIFICATION forming part of Letters Patent No. 379,339, dated March 13, 1888.

Application filed July 14, 1887. Serial No. 244,249. (No model.)

To all whom it may concern:

Be it known that I, GEORGE M. STEVENS, of Cambridge, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Fire- Alarm Signal-Boxes, of which the following, taken in connection with the accompanying drawings, is a specification.

My invention relates to fire-alarm signalboxes and to that class of such boxes termed non-interference signal'boxes; and it consists in certain novel features of construction,

arrangement, and combination of parts, which will be readily understood by reference to the description of the drawings, and to the claims to be hereinafter given.

Figure 1 of the drawings is a front elevation of my improved signalbox with the outer door opened to a position at right angles to the front face of the box and the inner door removed. Fig. 2 is a vertical section on line a: m on Fig. 1, and showing the parts to theleft of said line in elevation. Fig. 3 is a horizontal section through a portion of the apparatus on line 1 1 on Fig. 1. Fig. 4 is an elevation of the armature, the notched disk, the notch covering shield, and the pawl for operating said notched disk, and showing the outline of the lever for pulling the alarm, andnpon which said pawl is pivoted, in dotted lines.

In the drawings, A is the outer casing, pro vided with the hinged door A.

B is the intermediate casing, provided with the hinged door B, and O is theinner box, in which is placed the train of gearing and the spring which constitutes the motive power which operates the break-wheel, all of said boxes being insulated from each other in a weltknown manner.

Within the box 0 are firmly secured the plates a and a, connected together by suitable posts and properly insulated from said box, as shown in Fig. 3.

The main driving-shaft bis mounted in bearings in said plates a and a, and has firmly secured thereon the ratchetwvheel c, the arm (I, provided at its free end with the hook d and the disk 6, and also has loosely mounted thereon the pull-lever D, the guard-lever or notch- ;59 covering shield f, and the gear-wheel g. The

gear-wheel g has pivoted to its upper side the pawl g, the free end of which is pressed by the spring 9 into engagement with the teeth of the ratchet-wheel 0, so that said gear-wheel will be revolved by or with said ratchet-wheel when the shaft 1) is being revolved by the reaction of the spring E and remain in a state of rest when said shaft and ratchet-wheel are being turned in the opposite direction by pulling down the lever D.

The lever D has pivoted to its inner side the pawl 72, the free end of which is pressed into contact with the edgeof the disk 0 by the spring h.

The disk 6 has formed in its peripherya notch or detent, c, with which, when uncovered, the pawl h engages, so as to compel said disk and the shaft 1) to be moved about the axis of said shaft when the lever D is pulled down.

The guard lever or shield f, mounted loosely upon the shaft b or the hub of the disk 6, has three arms, 1, 2, and 3, the shorter arm, 1, extending just to the periphery of the disk 0, and is of sufficient width at its end to cover the notch e in said disk when in its normal position, the arm 2 being provided with the outwardly-projecting pin 4:, with which the cam or wedge-shaped lug t, secured to the inner surface of the door A, engages, when said door is closed, to move said lever around the axis of the shaft and thus cause the arm 1 to uncover the notch or detent c.

The leverfis maintained in its normal position relative to the disk 6, covering the notch e therein, by the spring i, secured by one end to said lever and at its other end to the disk e, andthe stop-pin i set in said disk, when not otherwise acted upon. I

The gear-wheel g engages with a pinion on the shaft j, upon which is secured the gearwheel j, which in turn meshes into a pinion on the shaft 75, upon which are secured the gear-wheel 7t and the break-wheel and the geanwheel it engages with a pinion on the shaft Z, upon which is secured the escapementwheel I, the teeth of which act upon the pallet Z which is provided with the pendulumarm P, all constructed and operating in a wellknown manner.

E is a main spring having one end secured to the shaft Z1, about which it is coiled, and secured by its other end to a stud, m, set in the frame-plate a in such a manner that the rotation or partial rotation of the shaft 1), caused by pulling down the free end of the lever D when the notch e is uncovered, will increase the tension of said spring.

F is a block,of hard rubber or other suitable insulating material, secured to an arm of the frame-plate a, and having secured thereon two spring-fingers, a, the free ends of which are arranged to make contact with the teeth of the break-wheel as it is revolved in a well-known manner.

When the pull-lever D has been pulled down to ring an alarm and is released, it is moved upward again by the reaction of the spring it until it is arrested by the insulated stop-pin if, set in the rim of the box 0, as shown in Figs. 1 and 2.

G is an electro-magnet secured in position in the box B, and provided with the armature 0, pivoted at 0, and provided with the arm 0 having secured to its free end a block of hard rubber, 0 in which is set the pin 19, which serves as a stop to limit the movement of the guard-lever f in the direction of the arrow f after an alarm has been pulled and when the armature is attracted into contact with the poles of the magnet by the arm 8 of said guardlever coming in contact with the said pin, as shown in Figs. 1 and 4.

The armature 0 has attached thereto the arm 19, carrying at its free end a hainmer,10 (see-Fig. 2,) which, when the armature is retracted from the magnet by the reaction of the spring 11 strikes the bell H and gives the signal. The backward movement of the armature is limited by the adjustable stop-screw q, and the tension of the spring 12 may be varied by moving the stem 1' in its bearing in the arm 1" and securing it by the set-screw 'r' A plate of hard rubber, I, is secured to the lower side of the box 13, upon which is secured the break-circuit key r and the metal plates g and (f, in which are set the screw-cups g and g, respectively, and a third plate, (not vshown,) in which is set the screw-cup 11 from which a wire (not shown) leads to the ground.

The left-hand wall of the box B has secured thereon a circuit-breaker of well-known construction, the operating-pin J of which is in position to be acted upon by the block J, secured upon the inside of the door A when said door is closed, and thus close the circuit through the shunt or short-circuit line and cutting the magnet out of the circuit while the door is closed, whereby a great saving is made in battery-power.

The wire upon which the current of electricity enters the box may be connected to the screwcup Q3, and the wire on which the current of electricity passes out of the box may be secured to the screw-cup q", or vice versa. The plate q is connected by the wire 8 to the screw cup t, which in turn is connected by the wire 8 to one of the spring-finger plates 12. The other spring-finger plate a is connected by the wire 3 to the screw-cup t, which in turn is connected by the wire 3 to the inner coil of the magnet G, the outer coil of which is connected by the wire 8 to the circuitbreaker key 1, which is normally in electric connection with the plate (1 The screw-cup t is also connected, through the wire 8 the circuit-breaker, and the wire s ,with the circuit-breaking key 1, thus forming a shunt or short circuit through which the current passes when the door A is closed, thus cutting the magnet out of the circuit. When said door is closed and the magnetis out out of the elec tric circuit, as above described, the armature 0,with its arm 0 is retracted into the position indicated in dotted lines in Figs. 1 and 4, and if the door A be open while an alarm is be iug rung in from any other box on the circuit the guard-leverfimmediately assumes the position indicated in dotted lines in Figs. 1 and 4, when the arm 1 of said lever covers the notch e in the disk e and efiectually prevents the pawl h from engaging with said notch, and as a consequence renders it impossible for an alarm to be rung in from this box until the alarm rung from the other box is completed and the door of this box has been shut and again opened. If, however, the door A be opened at a time when no other alarm is beiug rung in from any box on the circuit, the first movement of the door breaks the shunt or short circuit, thus sending the current through the magnet, causing it to attract the armature, which is thereby made to assume the position shown in full lines in Figs. land 4. A further movement of the door A per mits the reaction of the spring 1" to move the lever f in the direction indicated by the arrow f until the lower end of its arm 3 comes in contact with the pin p,-when the movement of said lever will be arrested with its arm 1 in such a position as to leave the notch e in the disk 6 uncovered, so that if the lever D be pulled down the pawl h will engage with said notch and partially rotate the disk 6, the shaft 1), the ratchet-wheel 0, and the hooked arm d and increase the tension of the main spring E. The train of gearing is prevented from revolving,after the proper-signal has been struck the requisite number of times,by the engagement of the hook d of the arm d with the pin 2", set in the gear-wheel k, and when the hooked arm dis moved from engagement with said pin d by pulling down the lever D, as above described,the tension of the main springE causes said train of gearing, with the break-wheel, to be revolved until the shaft b, carrying the arm (2, has been moved about its axis,in the direction indicated by the arrow f, asufficient distance 'for the hook d on said arm to again engage with the pin (2 and lock the train of gearing against further rotation. I

The door B of the boxB has cut through it a segmental slot for the passage of the hook D of the lever D, and also a slot for the passage of the pin 4,said slots not being shown, as they are of wellknown construction.

In some cases boxes are unprovided with the magnetGand its armature, in which case, in order to render the box effective for ringing in a second alarm after a first has been completed, an insulated stop-pin is set in the rim of the box, as at u,(see Fig. 1,) with which the lever f comes in contact before the disk 6 has completed its movement in the direction of the arrow f,t-hereby permitting the further movement of said disk to uncover the detentnotch e and thus place it in condition to be engaged by the pawl h at the next downward movement of the pull-lever D. By this ar rangement a second engagement of the pawl with the detent-notch is rendered impossible until the alarm rung by the first pull is completed, regardless of any number of pulls that may ignorantly or thoughtlessly be given to the lever D.

What I claim as new, and desire to secure by Letters Patent of the United States, is-- 1. In a signal-box, the combination, with the break-circuit wheel and the break-wheel motor mechanism, of a detent disk or wheel secured upon the main driving or spring-operated shaft of said motor mechanism, a guard lever or shield constructed and arranged to alternately cover and uncover the detent-notch in said disk, a pull-lever mounted loosely on said main shaft, and a pawl mounted upon said pull-lever and arranged to engage with said detent-notch when uncovered.

2. The combination, with the break-wheel and motor mechanism of a signal-box, of a detent disk or wheel secured upon the main driving-shaft of said motor mechanism,a guard lever or shield constructed and arranged to alternately cover and uncover the detent in said disk, a pull-lever loosely mounted on said main shaft, a pawl carried by said pull-lever and arranged to engage with said detent when uncovered, and a stoppin arranged to arrest the movement of said guard lever or shield caused by the reaction of the main spring of the motor before the motion of the detent disk or wheel in the same direction ceases.

3. The combination, with the break-wheel and motor mechanism of a signal-box, of a detent disk or wheel secured upon the main shaft of said motor mechanism, a guard lever or shield constructed and arranged to alternately cover and uncover the detent'notch in said disk, a pull-lever mounted loosely upon said main shaft,- a pawl carried by said lever and arranged to engage said detent when uncovered,an electro-magnet,and a pivoted armature provided with an insulated stop-pin arranged to arrest the movement of said guardlever caused by the tension of the main spring of the motor mechanism when the armature is attracted by said magnet and to be removed from the path of said guard-lever when said armature is retracted, substantially as described.

7 4. The combination, with the breakwvheel and motor mechanism of a signal-box, of a detent disk or wheel secured to the main driving-shaft of said motor mechanism, a guard lever or shield constructed and arranged to alternately cover and uncover the detentnotch in said disk, a pin projecting outward from said guard-lever, a pull-lever mounted loosely upon said main shaft, a pawl carried by said lever and arranged to engage said detent when uncovered, an electro-magnet, a pivoted armature provided with a stop-pin constructed and arranged to limit the movement of said guard-lever in one direction when the armatureis attracted by the magnet and to be removed from the path of said guard-lever when the armature is retracted,

and a lug secured to the outer door of said box and arranged to engage with the pin projecting from the guard-lever and move said lever about its axis of -motion when said door is closed, substantially as described.

5. In a fire-alarm signal-box, the combination of a pull-lever loosely mounted upon the main driving-shaft of the break-wheel motor mechanism, a pawl mounted upon said lever, a detent-wheel mounted upon said shaft in position to be acted upon by said pawl, a detent shield or guard also mounted upon said shaft and constructed and arranged to cover the side of the notch in said detentwheeland prevent the pawl engaging therewith and movable about said shaft to uncover said detent-notch, an electro-magnet, and an armature provided with a pin constructed and arranged to engage with an arm of said shield to limit its movement when said armature is attracted by its magnet and to be moved from the path of said shield arm when the armature is retracted.

6. In a fire-alarm signahbox, the combination, with the break-wheel and the motor mechanism for rotating thesame, of a pull'lever loosely mounted upon the main driving-shaft, a pawl mounted upon said lever, a detentwheel mounted upon said shaft in posit-ion to be engaged by said pawl, a shield or guard also mounted upon said shaft and constructed and arranged to cover the notch in said detent-wheel and prevent the pawl engaging therewith, and movable about said shaft to uncover said detent-notch, a lug upon the outer door of the box constructed and arranged to engage with a pin projecting lat erally from an arm of said shield to move said shield in one direction when the door is being closed, a spring arranged to move said shield in the opposite direction when the door is opened, a magnet, an armature provided with a pin arranged to engage with an arm of the detent-covering shied and limit its movement when said armature is attracted and the door is opened, and a shunt or short circuit with a circuit-breaker therein operated IIO IIS

by the door of the b0x,which c0-operateswith to this specificati0n,in the presence of two subsaid circuit-breaker and shield, as described, scribing witnesses, on this 12th day of July, whereby the circuit-breaker is opened and the A. D. 1887.

armature attracted before the shield is released GEORGE M. STEVENS. 5 by the lug on the door, substantially as de- Witnesses:

scribed. N. O. LOMBARD,

In testimony whereof I have signed my name WALTER E. LOMBARD. 

